1. Technical Field
The invention relates to a thermal triggering element for sprinklers, valves or anything similar in the form of a completely enclosed compartment with a container that is filled with a shattering fluid.
2. Background Information
Thermal triggering elements for sprinklers as well as for other valves, such as, for example, emergency release valves of gas containers, that are configured having containers with a hollow space on the inside, completely enclosed and filled with a shattering fluid, have been known and taught by the prior art for quite some time. The containers therein are in most instances made of glass; they can also be referred to as glass bulbs.
Such glass bulbs that are used as a thermal triggering element are specified, for example, in DE 36 01 203 A1.
Triggering elements of this kind are filled with a shattering fluid that expands upon its being heated resulting in the shattering of the container that is typically loaded in a valve seat and holds the valve in its closed position, thus resulting in the triggering action of a valve or the like.
Different materials have been proposed as shattering fluids. U.S. Pat. No. 4,938,294, for example, discloses toluene, xylene, trichloroethylene, tetrachloroethylene and/or mixtures thereof as expedient shattering fluids. EP 0 838 242 B1 discloses a halogen derivative of an aromatic hydrocarbon having two or more halogen substituents, an aliphatic amide as well as mixtures thereof as expedient shattering fluids.
DE 197 80 041 C1 specifies a substance that is derived from a halogen-free or a halogenated hydrocarbon as expedient shattering fluid having as part of its structural formula                a)                    i) at least one CH2 group substituted by oxygen (O), sulfur (S), sulfinyl (SO) or sulfonyl (SO2); or having            ii) at least one CH group substituted by nitrogen;                        b) no hydrogen atoms that are directly bonded to oxygen, nitrogen of sulfur;        c)                    i) at least one ring; or            ii) at least two oxygen atoms with two single bonds, respectively; or            iii) at least two carbonyl groups of ketones and/or aldehydes; or            iv) at least one oxidized sulfur atom (SO or SO2); or            v) at least one nitrogen atom in form of an amide, imide, imine or nitrile.                        
DE 20 2009 007 987 U1, finally, proposes as a shattering fluid hydrocarbons or a mixture of hydrocarbons of the group below:                a) an aliphatic bromide;        b) a hydrocarbon with a nitro group;        c) a single-halogenated benzene ring;        d) an aliphatic ester compound having two double-bonded oxygen atoms, respectively.        
Although all the aforementioned triggering fluids have proven effective, in principle, and they are basically expedient options for use in triggering elements according to the class, nevertheless, there exists a continuing demand for improvement, in particular in view of the aspects as indicated below: